1. Technical Field
This invention relates generally to automotive air conditioners, and particularly to an automotive air conditioner that includes a warm-air bypass passage to boost heating capacity.
2. Discussion
Conventionally, an automotive air conditioner includes an air-mixing door to regulate the mixing ratio of chilled air, which has passed through an evaporator and bypassed a heater core, and warm air which has passed through the heater core.
In many conventional automotive air conditioning systems, the chilled-air passage through which chilled air flows is disposed above the heater core, and the warm-air passage through which the warm air flows extends from below to above the heater core, so that the chilled air and the warm air are mixed within the air-mixing chamber in the space above the heater core. Subsequently, after the chilled air and warm air are mixed by the air-mixing door, warm air flowing in an upward direction is reversed so as to flow in a downward direction, and then is blown from through a foot vent.
Additionally during a maximum heating condition, the air-mixing door causes all chilled air passing through the evaporator to pass through the heater core, and all conditioned air flows through the warm-air passage and blows through the foot vent. The blown-air path to the foot vent requires that the blown air direction to be reversed, as described above, thereby increasing air resistance and the production of conditioned air.
As a result, in such conventional systems, a bypass passage operative to cause the warm air to bypass the warm-air passage, and a bypass door operative to open and close the bypass passage, are provided. During maximum heating, the warm-air bypass door opens the bypass passage, thereby reducing air resistance and improving heating capacity.
However, when the bypass passage is abruptly opened or closed by the warm-air bypass door as warm air is blown through the foot vent, air resistance abruptly changes, and air quantity changes suddenly due to the switching of the warm-air bypass door. As a result, the blown-air temperature also fluctuates.